我在D3中使用json数据时遇到问题。从我看到的console.log
这个事实来看,文件被正确读取,并且似乎根据我找到的所有示例的方式进行了正确的格式化。但是,当我尝试使用.data(function(json_data){return json_data.accessibility;})
做一个嵌套选择时,我得到:“不能读取未定义的属性'长度'。尝试嵌套选择时未定义D3数据
我的功能:
//load scenario json data
d3.json("./SupportTool/scenario1result.json", function(error, json_data){
if(error) {return console.warn(error)};
console.log(json_data); //works
// add main SVG block
var svg = d3.select(d3id)
.append('svg')
.attr('width', 300)
.attr('height', 75)
.attr('id', 'svgblock');
// add an SVG group element for each scenario
var series = svg.selectAll('g.series')
.data(d3.keys(json_data))
.enter()
.append('g')
.attr('class', 'series');
var circles = series.selectAll("circle")
.data(function(json_data){return json_data.accessibility;})
.enter()
.append("circle");
var circleAttributes = circles
.attr("cx", 20)
.attr("cy", 20)
.attr("r", 20)
.style("color","blue"); });
我的JSON数据:
{
"meta":[{"sc":"1"},{"stratid":"1"}],
"accessibility":[
{"pop400":"77"},{"pop800":"86"},{"jobs800":"78"},{"pop400tr":"41"},{"pop800tr":"69"},{"jobs800tr":"80"}
],
"housing":[
{"newcom":"0"},{"redev":"100"},
{"apt5":"6"},{"apt4":"65"},{"twn":"14"},{"sglf":"15"},
{"urb":"0"},{"urbhec":"0"}
],
"transport":[
{"walk":"55"},{"transit":"18"},{"auto":"27"},
{"vkt":"11000"},
{"kmtr":"502"},{"form":"grid"},
{"lanekm":"3250"},
{"ghgtr":"67"},{"ghgres":"75"}
],
"costs":[
{"roadcapbils":null,"roadcap":null},
{"transitcapbils":null,"transitcap":null},
{"watercapbils":null,"watercap":null},
{"firecapbils":null,"firecap":null},
{"reccapbils":null,"reccap":null},
{"educapbils":null,"educap":null}
],
"opcosts":[
{"roadopbils":null,"roadop":null},
{"transitoppbils":null,"transitop":null},
{"wateropbils":null,"waterop":null},
{"fireopbils":null,"fireop":null},
{"parksopbils":null,"parksop":null}
] }
谢谢!它的伟大工程,当我和 'VAR圈更换整个系列和圆块= svg.selectAll( “圆”) \t \t \t \t \t。数据(json_data.accessibility) \t \t \t \t \t。进入() \t \t \t \t \t .append(“circle”);'' –